Conventional filter cigarettes typically include a filter made of a cellulose acetate tow which becomes stained at the mouth end of the filter as the cigarette is smoked. Some smokers consider this stain to be objectionable notwithstanding the fact that the stain is a visual indicator that the filter is operating efficiently and effectively. There have been attempts to eliminate this stain or at least minimize the smoker's perception of the stain both visually and from a taste standpoint, for example, by the provision of a recess at the mouth end of the filter. However, many smokers consider the recessed-end filter also to be objectionable regardless of its effectiveness in eliminating or reducing the visual or taste perception of the stain at the mouth end of the filter.
It would be desirable therefore to provide a filter for a smoking article, such as a cigarette, in which the mouth end of the filter exhibits little or no staining during smoking. At the same time, such filter should provide filtration effectiveness equivalent or substantially equivalent to the conventional cellulose acetate filters.
It is well known to enhance or alter the taste or flavor of cigarettes providing the tobacco and/or filter of the cigarette with a flavorant additive. One problem associated with the addition of flavorants to cigarettes and cigarette filters is the migration of the flavorant from the cigarette or filter to the cigarette packaging material or to the surroundings when the cigarette package is opened. It would be desirable to incorporate a flavorant additive in a cigarette in such a way that migration of the flavorant prior to smoking the cigarette is minimized but that upon lighting and smoking the cigarette, release of the flavorant additive is accelerated so that it is readily perceived by the smoker.